search for: duse_rinternals

...ort <Rinternals.h> int main() { SEXP a, b; // ... CAR(a) = b; } --8<--- If I compile this with "gcc -I <path to R 2.6.2> foo.c", I get the error "invalid lvalue in assignment", while it compiles without error if I specify the compiler option "-DUSE_RINTERNALS". Looking at the output of the preprocessor output reveals that without USE_RINTERNALS, the line "CAR(a)=b" stays as it is, i.e. presents the compiler with a function call as l-value, while with USE-RINTERNALS, it gets macro-expanded to "((a)->u.listsxp.carval) = b",...